One of earth’s most important organisms are called diatoms. Responsible for 40% of ocean productivity, the main factor that limits growth is nutrient availability. Nutrients are quickly absorbed by all algae and competition is fierce. Some algae swim which helps to absorb nutrients. Diatoms cannot swim which is a big disadvantage. However diatoms have a trick up their sleeve! We show that diatoms rapidly change buoyancy on time scales of milliseconds and alternate between a fast and slow sinking phases. We demonstrate that this allows these seemingly poor competitors to outcompete even active swimmers for precious nutrients and explains their ability to dominate the oceans.